Method and apparatus for texture analysis

Abstract

In analyzing the texture of rolled metal sheets and strips by means of X-rays or γ-rays that penetrate them, the total beam emitted by the source of radiation is divided by collimators into several component beams, and each component beam is aimed at a different angle at a component area of the sheet or strip being tested. The diffracted radiation that penetrates the sheet is analyzed in accordance with its energy distribution in detectors and the results are processed in a computer.

We claim: 
     
       1. Apparatus for testing and determining textural coefficients in rolled metal sheets and strips having a crystalline structure comprising: means for moving a sheet or strip along a predetermined path; means for aiming a plurality of beams simultaneously from a fixed source of X-rays or gamma-rays at different angles at a plurality of component areas of aid sheet or strip being tested and analyzed in terms of each component area, said X-rays or gamma-rays penetrating through the entire thickness of said sheet or strip for measuring texture through said entire thickness, said plurality of component areas being irradiated, by said beams at different angles of incidence to said component areas, said component areas comprising islands with regions between the islands being free of incident X-rays or gamma-rays; said X-rays or gamma-rays penetrating said sheet or strip and being diffracted by the crystalline structure of said sheet or strip; means for analyzing and calculating texture data dependent on crystal orientation in said crystalline structure to compute coefficients of texture in terms of a non-textured reference; means for obtaining results from said component areas and assigning said component areas to textures during further processing, and for treating the results obtained from said component areas in further processing of the results as if the results had been obtained from only one component that had been irradiated at the same angles as said plurality of component areas are irradiated at; a source of radiation for irradiating said plurality of component areas; a system of detectors positioned away from said source and inside a pencil of rays from said source; analyzers connected to processing means in the form of a computer; passage means between said source of radiation and a detector for a sheet or strip being tested; a system of collimators with apertures positioned directly in front of a window through which radiation leaves said source; at least one detector and an associated downstream analyzer for component radiation from each collimator aperture. 
     
     
       2. Apparatus as defined in claim 1, wherein said source of radiation comprises an X-ray tube. 
     
     
       3. Apparatus as defined in claim 1, wherein said source of radiation comprises gamma-radiation sources. 
     
     
       4. Apparatus as defined in claim 1, including analyzer means connected to a plurality of detectors, said detectors being positioned in vicinity of round annular diffraction beams. 
     
     
       5. Apparatus as defined in claim 1, wherein each of said detectors comprises a single crystal, a plurality of said detectors being integrated into a chilled system of detectors. 
     
     
       6. Apparatus as defined in claim 1, wherein said detectors are positioned so that occurring predetermined positions are masked according to predetermined sheets and strips for a substantial change in intensity in relation to changes in texture. 
     
     
       7. Apparatus as defined in claim 1, wherein said source of radiation has an 80 to 160 kV X-ray tube for testing sheets of steel having a thickness exceeding 2 mm. 
     
     
       8. Apparatus as defined in claim 1, wherein said detectors have positions dependent on test results with an untextured reference, said positions of said detectors being programmed into a computer as reference values. 
     
     
       9. Apparatus as defined in claim 1, wherein anisotropies in sheets having a thickness exceeding 2 mm are determined at four to eight test areas, three to seven diffraction reflections per detector being available for processing. 
     
     
       10. A method for analyzing texture of rolled metal sheets and strips having a crystalline structure, comprising the steps: moving a sheet or strip along a predetermined path; aiming a plurality beams simultaneously from a fixed source of X-rays or gamma-rays at different angles at a plurality of component areas of said sheet or strip being tested and analyzed in terms of each component area, said X-rays or gamma-rays penetrating through the entire thickness of said sheet or strip for measuring texture through said entire thickness, said plurality of component areas being irradiated by said beams at different angles of incidence to said component areas, said component areas comprising islands with regions between the islands being free of incident X-rays or gamma-rays; said X-rays or gamma-rays penetrating said sheet or strip and being diffracted by the crystalline structure of said sheet or strip for analyzing and calculating texture data dependent on crystal orientation in said crystalline structure to compute coefficients of texture in terms of a non-textured reference; obtaining results from said component areas and assigning said component areas to textures during further processing, and treating the results obtained from said component areas in further processing of the results as if the results had been obtained from only one component area that had been irradiated at the same angles as said plurality of component areas are irradiated at. 
     
     
       11. A method as defined in claim 10, wherein said sheets and strips move longitudinally while being tested and analyzed. 
     
     
       12. A method for analyzing texture of rolled metal sheets and strips having a crystalline structure, comprising the steps of: moving a sheet or strip along a predetermined path; aiming a plurality of beams simultaneously from a fixed source of X-rays or gamma-rays at different angles at a plurality of component areas of said sheet or strip being tested and analyzed in terms of each component area, said X-rays or gamma-rays penetrating through the entire thickness of said sheet or strip for measuring texture through said entire thickness, said plurality of component areas being irradiated by said beams at different angles of incidence to said component areas, said component areas comprising islands with regions between the islands being free of incident X-rays or gamma-rays; said X-rays or gamma-rays penetrating said sheet or strip and being diffracted by the crystalline structure of said sheet or strip for analyzing and calculating texture data dependent on crystal orientation in said crystalline structure to compute coefficients of texture in terms of a non-textured reference; obtaining results from said component areas and assigning said component areas to textures during further processing, and treating the results obtained from said component areas in further processing of the results as if the results had been obtained from only one component area that had been irradiated at the same angles as said plurality of component areas are irradiated at; and collimating radiation from one source for irradiating each component area. 
     
     
       13. A method as defined in claim 12, wherein three to eight component areas are irradiated when the rays are X-rays and 15 to 20 component areas are irradiated when the rays are gamma-rays.